Center-feed roll unit and dispenser incorporating such center-feed roll unit

ABSTRACT

A center-feed roll unit for dispensing a web, especially a web of paper or nonwoven material, is disclosed. The center-feed roll has an inner center hole and a minimum inner diameter D min  defined before a first use of the center-feed roll. A length L of the center-feed roll in a longitudinal direction is perpendicular to the minimum inner diameter D min , and the enter-feed roll includes a first end and a second dispensing element. The center-feed roll unit includes an untwisting insert element provided in the center hole. The insert element is elongate and extends from the first end of the center-feed roll essentially along the longitudinal direction, and has an extension x in the longitudinal direction of 0.5· L&lt;x &lt;1.5· L.

FIELD OF THE INVENTION

The invention relates to a center-feed roll unit for dispensing a web, especially a web of paper or nonwoven material with the features of the pre-characterizing part of claim 1. Further, the invention relates to a dispenser for a web of material with such a center-feed roll unit.

BACKGROUND OF ART

Center-feed roll units are known in the art. They include center-feed rolls which commonly consist of a web material which is fed from the center of the roll out of the roll. When such center-feed roll unit is installed in a corresponding dispenser, the web material is dispensed through an aperture of the dispenser.

Dispensers with center-feed rolls are often found in public rest rooms, and in hospitals and industry for use as a dispenser for handtowels or for tissues or towels for general cleaning purposes. Further, dispensers with center-feed rolls are used in a home environment, especially in kitchens.

Center-feed rolls encounter the problem that a web taken from the inside of a center-feed roll tends to leave the roll and the corresponding dispenser in a twisted shape. In other words, the paper is wound up from within the roll making a twirl. This twirl lingers in the web material and makes it twisted after dispensing.

EP 0 480 848 B1 relates to a dispenser of paper towel unwinding from the inside and having a chimney-shaped part which is provided around the bottom central opening. This chimney-shaped part extends upwards inside the core of the roll and has the purpose to straighten out the paper which has become twisted and creased during its unwinding from the inside of the roll.

Depending on the vertical extension of the upwards standing roll and depending on the size of the chimney-shaped part around the dispensing hole at the bottom of the roll, the problem of twisting cannot be reliably prevented.

DISCLOSURE

It is the object of the present disclosure to provide a center-feed roll unit and a dispenser incorporating such center-feed roll unit which makes a web in such center-feed roll untwist on its own during the dispensing step.

This object is solved by a center-feed roll unit with the features of claim 1 and a dispenser for a web of material with an inventive center-feed roll unit. Additional advantageous features follow from the dependent claims.

The center-feed roll unit according to the present disclosure for dispensing a web, especially a web comprising paper or nonwoven material, has a center-feed roll with an inner center hole having a minimum inner diameter D_(min) defined before its first use, as well as a length L of the roll in a longitudinal direction perpendicular to the minimum inner diameter. Consequently, the center-feed roll has a first end and a second dispensing end in a longitudinal direction. The inventive center-feed roll unit is characterized in that the device comprises an untwisting insert element provided in the center hole, the insert element being elongate and extending from the first end essentially along the longitudinal direction; and having an extension x in the longitudinal direction of

0.5·L<x<1.5·L.

The untwisting insert element extends from the first end of the roll along its longitudinal direction. The first end is opposite to the second dispensing end of the roll. This means that, in case that the center-feed roll unit is placed such that its longitudinal direction is vertically oriented with the dispensing end at the bottom, the untwisting insert element extends from the upper, first end and depends into the inner center hole towards or even beyond the lower dispensing end of the roll. However, it should be noted that the center-feed roll unit can be also arranged such that its longitudinal direction extends in a horizontal or any angular direction.

Such specific arrangement has been found to provide superior effects compared to solutions as given in the prior art.

The dispenser according to U.S. Pat. No. 5,215,211 has an insert stabilizing element which partly extends within the inner center hole of the roll. However, this stabilizer part partially penetrating the hole in the center of the supply of connected sheets serves to stabilize the supply and prevents it from caving in upon itself when most of the sheets have been dispensed from the supply. Such stabilizing element according to U.S. Pat. No. 5,215,211 does not serve the purpose of preventing the paper sheets dispensed from twisting. The same applies to EP 0 107 487 A1 also disclosing a spigot acting as a support for the roll and maintaining it in position, particularly when a considerable proportion of the roll has been dispensed from the center of the roll. Thus, the spigot counteracts a possible collapsing of the roll.

The function of the untwisting insert element can be described as follows. When the web is dispensed from the center of the center-feed roll, there is a circular movement affecting the web material. This movement is either in clockwise direction or counter clockwise direction depending on which side of the roll is used for dispensing. This first movement is kept in the web and makes the tail twisted. In addition to this first movement, there is a second circular movement creating an inner twirl in the opposite direction to the first movement. When using the elongate untwisting insert element according to the present disclosure, this insert element comes to be in the center of the inner twirl and stabilizes the inner twirl and its movement opposite to the first movement all the way to the dispensing opening of the roll just before the web is dispensed. In such a way, the web is forced to untwist after dispensing because the two twisting movements in opposite directions neutralize each other.

Good results of the untwisting effect can be achieved if the extension x in the longitudinal direction of the insert element is

0.6·L<x<1.5·L

and preferably

0.8·L<x<L.

The center-feed roll can have a maximum inner diameter at or close to full consumption of the web, wherein the longitudinal extension x of the insert element equals at least half of the maximum inner diameter of the center-feed roll. This adds a further requirement with regard to the longitudinal extension of the insert element. It is often automatically fulfilled by the subject matter of claim 1. However, in cases in which a roll having a relatively large thickness of the material wound is used, the geometrical situation when dispensing the web can differ significantly between the first use of the center-feed roll and the situation at the final consumption of the roll. In such a case, the minimum longitudinal extension of the insert element should also fulfill the above requirement with respect to the maximum inner diameter of the center-feed roll.

The relevant diameter of the insert element is larger than 0.1·D_(min) and smaller than 0.99·D_(min), preferably in the range between 0.6·D_(min) and 0.95·D_(min) and most preferably in the range between 0.8·D_(min) and 0.9·D_(min). It can be seen that the length of the insert element is more important than the diameter of the insert element and that even a relatively small space between the web to be dispensed and the insert element extending inside the center hole can be provided as long as it is still possible to dispense the web without problems. In this context, the term “relevant diameter” is defined as the inner diameter of the smallest tube which can still house the insert element.

The insert element may be made of disposable material, preferably cardboard. This is especially advantageous in case that the insert element does not form part of the dispenser but is part of the replacement rolls for a dispenser. In such a case, the insert element can be disposed of after the final consumption of each center-feed roll.

The insert element may be made of glass, wood, silicone, rubber, metal or plastic material. This list of possible material shows that there is a broad range of possible materials that can be used for the insert element. This broad range of materials shows that it is mainly the position and geometry of the insert element which is important, whereas its material is of smaller importance. Nevertheless, some material characteristics are also important because the web to be dispensed slides over the surface of the insert element. Therefore, depending on the material of the web to be dispensed, the surface of the insert element should be suitable, e.g. in order to prevent undesired abrasion and dusting effects in the dispenser. In order to avoid such problems, the insert element according to a further embodiment has a smooth surface.

The insert element can have a cross-sectional shape which is circular, semi-circular, elliptical, crescent-shaped or prismatic, especially triangular. Tests conducted with different cross-sectional shapes of the insert element revealed that the cross-sectional shape has a smaller impact on the overall performance of the untwisting operation achieved by the insert element compared to the length of the insert element. However, the above given shapes all prove to provide good results.

The insert element can also consist of separate parallel rods.

Further, an insert element can be used which is a flat elongate strip. This has the advantage that the insert element is easy to manufacture, especially if it is made of disposable material like cardboard.

The dispenser may be characterized in that the insert element is removably attached to the dispenser close to the first end of the center-feed roll loaded into the dispenser. If the first end of the center-feed roll is its top end, the longitudinal direction or the center-feed roll is essentially vertical. This is a quite common orientation of the center-feed roll within a dispenser. The center-feed roll is inserted such that its longitudinal direction is essentially vertical and the insert element is lowered from the upper end of the roll into the hollow core of the roll. A removable attachment of the insert element simplifies the exchange of the roll. In such a case, it is possible to remove the insert element and to attach it again to the housing of the dispenser once a new roll has been correctly inserted in the dispenser.

Alternatively, the insert element may be attached to the dispenser by means of a form-fit connection, snap fit, slide-in connection or by an adhesive means like double-sided adhesive.

However, the insert element can also be hingedly attached to the dispenser. This has the advantage that the insert element needs not to be removed when replacing the center-feed roll. The attachment of the insert element by means of a hinge is especially advantageous if the insert element is made of a flexible material so that it can be bent during its insertion into the center hole of the roll.

The insert element may be provided as a separate part insertable into the center-feed roll before its loading into the dispenser. In that case, different designs are possible. According to a first alternative, the insert element is not attached to the housing of the dispenser but forms part of the center-feed roll unit. In this case, a possible design of such insert element could be a plate-like flange element to which the elongated shaped insert to be placed into the center hole of the roll is attached. The insert extends in a direction perpendicular to the main surfaces of the plate-like flange. The flange element has to be shaped such that it rests on the center-feed roll up to the point of time when it has been completely used up.

According to a second alternative, the insert element as described with respect to the first alternative, forms part of a replacement kit together with an exchange roll. After the replacement kit has been loaded into the dispenser, the flange element of the insert element is attached to the dispenser body. When the center-feed roll has been used up, the insert element is detached from the dispenser body and disposed together with the center-feed roll.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in more detail by way of example only with reference to the following embodiments in which

FIG. 1 schematically shows a dispenser including a center-feed roll inserted therein and with an untwisting insert element;

FIG. 2 and FIG. 3 schematically shows a center-feed roll in order to show the dimensions used for determining the optimum dimensions of the insert element;

FIG. 4 shows an example of an insert element;

FIG. 5 shows possible cross-sectional shapes of an insert element; and

FIG. 6 and FIG. 7 are schematic cross-sectional views of a center-feed roll without an insert element and a center-feed roll with an insert element to show the untwisting effect of the insert element.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following embodiments throughout the drawings the same elements will be denoted by the same reference numerals.

In FIG. 1, a center-feed roll 10 inserted in a dispenser 20 is schematically shown. The dispenser 20 is only shown schematically because embodiments of the invention can be used in a wide variety of different dispensing devices as long as they house a center-feed roll and are provided with a suitable dispensing opening through which the web to be dispensed, particularly a web comprising one or more plies of paper or nonwoven material, can be removed. The web can be provided with transverse perforations so that a user can easily remove a desired length of the web. As an alternative or in addition to this, the dispensing opening of the dispenser 20 can be provided by means for severing the web, like teeth with tear edges which penetrate the web and weaken the web to an extent that a user can easily remove a desired length from the web.

Further, the dispenser 20 can usually be opened in a suitable way so that service personnel gains access to the interior of the dispenser. The cover element of the dispenser can be hingedly attached to the backside wall which usually is attached to a wall in a room. However, it is also possible that the cover can be removed by lifting it in a vertical direction upwards or downwards. Such different arrangements to open the dispenser are not shown in FIG. 1 because they are known in the field of dispensing devices. The same applies for a suitable support structure to hold the center-feed roll thereon. This can be a plate-like element with a center hole which supports the lower end 12 of the center-feed roll. However, alternative means like gripping arms are also possible. The center-feed roll 10 is provided with a center hole 14 which has an essentially cylindrical shape and extends along the longitudinal axis of the center-feed roll 10 from the lower end 12 to the upper end 16 of the roll. As will be shown later, the size of the center hole 14 depends on the degree of consumption of the web and ranges between a minimum diameter and a maximum diameter.

As can be seen in FIG. 1, there is an untwisting insert element 30 which is arranged inside the center hole 14 and, in the specific example as shown in FIG. 1, is attached at the hinge 32 to a housing part of the dispenser. However, this only serves as an example and it will be apparent to a person skilled in the art that alternative ways to attach the insert element to the dispenser are also possible, like a form-fit connection, e.g. a hook-in attachment, a snap fit, a slide-in connection or a clamping connection, but also an adhesive connection e.g. by using double sided adhesive. An easy to use connection is the use of velcro strips.

In the example as shown in FIG. 1, the insert element 30 extends essentially along the whole length of the center-feed roll between the upper end 16 and lower end 12. The web product e.g. paper product 18 leaving the dispenser is schematically shown together with arrows A indicating the direction in which a user tears the tail end of the web in order to dispense a suitable length of web material.

As can be seen in FIG. 2, the center-feed roll 10 has an overall length L in its longitudinal direction between the upper end 16 and lower end 12. Although, in this special embodiment, the longitudinal direction of the center-feed roll is in a vertical direction, any other angular orientation can be used as well. Before its first use, the center hole 14 has a diameter D_(min) which is the minimum diameter that is continuously increased during the dispensing of the web product. This is again exemplified in FIG. 3 showing a cross-sectional view from the upper end 16 of the center-feed roll 10. Before its first use, the center hole 14 has the minimum diameter D_(min) and when the web wound into the roll has been completely used up, the diameter has increased up to its maximum diameter D_(max) as shown in FIG. 3. The center hole might not have a circular cross-section, but could be deformed e.g. to an elliptical shape. In such a case, the minimum diameter is defined as the maximum outer diameter of a cylindrical element which can be introduced into the center hole before the first use of the roll.

FIG. 4 shows the untwisting insert element 30 which, in the example case according to FIG. 4 differs from that as shown in FIG. 1. The insert element 30 according to FIG. 4 can be used without attaching it to a dispenser. It simply has to be inserted from the upper end 16 of a center-feed roll 10 such that the flange element 32 as schematically shown in FIG. 4 rests on the upper end 16 of a center-feed roll, whereas the elongate portion 36 of the insert element 30 extends into the center hole of a center-feed roll.

As can be seen in FIG. 4, the elongate portion 36 has a length x and a diameter Ø, the range of which will be specified below.

In order to achieve the desired untwisting effect, the length x ranges between 0.5·L and 1.5·L. However, the optimum range was found to be close to the length L of the center-feed roll so that the insert element should extend almost all the way from the first end to the dispensing end of the roll. The optimum length of the elongate portion follows from the following equation:

0.8·L<x<L.

A further geometrical requirement relates to the minimum length X in case that the maximum inner diameter of the center-feed roll is relatively large. This can be the case for rolls having a high material thickness. In such a case, the following equation should also be fulfilled:

x>D _(max)/2

In other words, the length of the insert element should be more than half of the maximum diameter of the center-feed roll so that, also in case of a relatively large center hole, the desired effect of the untwisting insert element can still be realized.

As regards the diameter of the elongate portion of the untwisting insert element, it has to be smaller than the minimum diameter so that, also in case of a web material having a relatively high flexibility and compressibility, the web material can still be removed without undue force. Even if in some cases it could be possible to provide an elongate portion of an insert element with a diameter slightly exceeding D_(min), such dimension should be avoided because the web material can tear at the very start of the dispensing operation and, the service personnel could damage the web material when inserting the insert element.

As regards the diameter of the elongated portion of the insert element, a relatively high range of diameters is possible:

0.1D _(min)<Ø<0.99D _(min)

However, in order to achieve better results, the following range should be selected:

0.6D _(min)<Ø<0.95D _(min)

The optimum results have been obtained within the following range:

0.8D _(min)<Ø<0.9D _(min)

If the length of the insert element is long enough, the diameter can be selected to be relatively small.

In the above equations, a diameter of the elongate portion of the insert element was given. However, as can be seen in FIG. 5, different cross-sectional shapes of the elongate portion of the insert element are possible. Therefore, the diameter as used in the above equations is defined to be the inner diameter of the smallest possible tube which can be used to pass over the elongate portion of the insert element.

As can be seen in FIG. 5, very different cross-sectional shapes of the insert element can be used. These are, starting from the top in the left column of FIG. 5 a circular shape, a semicircular shape, a triangular shape or plate-like shape as exemplified in FIG. 1.

Besides these shapes, also good results could be achieved with an insert element, the cross-sectional shape of which resembles the letters C or S. Moreover, it could be seen that the elongate portion of the insert element can consist of several independent elements like three rods 38 which are oriented in a geometric arrangement of a triangle with each side having the same length.

The insert element and especially its elongate portion can be manufactured from a wide variety of materials like wood, glass, plastic materials, rubber, metal or silicones. However, it is also possible to use a disposable material e.g. made of cardboard. Such disposable material is especially advantageous in case of an insert element as shown in FIG. 4 which is not attached to the dispenser body but supported by the center-feed roll so that each replacement roll can already be provided with an insert element and service personnel can easily replace the center-feed rolls without the need for further steps.

FIGS. 6 and 7 schematically show the function of the untwisting insert element 30. In the example as shown in FIG. 6, there is no insert element in the center hole 14 of the roll. During the dispensing of the web, the web of material is wound off the wall of the center hole 14, in the example as shown in FIG. 6 in the clockwise direction 40. Whether this movements is in a clockwise or counter clockwise direction only depends on the fact which side up the center-feed roll is used for dispensing the web. However, for the description of the twisting and untwisting effect, the direction is not important as long as all directions as stated herein are simply reversed.

Besides the first clockwise direction 40, a twirl 42 is formed on the inside of the center hole 14. This twirl is formed by a second movement in the opposite direction, in the specific example in the counter clockwise direction 44. This leads to a web of material dispensed which is twisted in the first direction 40. If an insert as shown in FIG. 7 is used, the web 18 is wound off the wall again in a clockwise direction 40. Again, a twirl 42 is formed on the inside of the center hole 14 in the opposite direction which, in the specific case, is a counter clockwise direction. This twirl 42 is stabilized and “stored” by the insert element 30 all the way over its length x towards the dispensing end of the roll. After the web 18 has left the end x of the insert element, the two movements in a counter clockwise direction and in clockwise direction neutralise each other so that the paper automatically untwists after dispensing.

The provision of an untwisting insert element of an elongated shape which extends from the first end of a center-feed roll almost all the way to the dispensing end leads to the astonishing effect that, although the web dispensed also performs two different movements in two different rotational twisting directions, these two opposite twisting directions neutralise themselves so that a web of material can be removed which is essentially untwisted. When the user pulls out a paper it is still twisted but when the user releases the tail before tearing the web, the web “remembers” the two twisting directions imposed on the web and untwists by itself so that a user is presented by a much wider tail of the web to tear off compared to conventional center-feed dispensing systems. 

1. A center-feed roll unit for dispensing a web of material, the center-feed roll unit comprising: a center-feed roll having the web of material and having an inner center hole with a minimum inner diameter D_(min) defined before a first use of the center-feed roll, a length L of the center-feed roll in a longitudinal direction being perpendicular to the minimum inner diameter D_(min), and the center-feed roll including a first end and a second dispensing end; and an untwisting insert element provided in the center hole, the untwisting insert element being elongate and extending from the first end of the center-feed roll essentially along the longitudinal direction, and having an extension x in the longitudinal direction of 0.5·L<x<1.5·L, wherein, dispensing the web of material from a center of the center-feed roll causes a first circular movement of the web of material and an inner twirl in the opposite direction to the first circular movement, and the untwisting insert element is provided to be in the center of the inner twirl to stabilize the inner twirl and inhibit further movement of the inner twirl in a direction opposite to the first circular movement, so that the web of material untwists after dispending.
 2. The center-feed roll unit according to claim 1, the untwisting insert element having an extension x in the longitudinal direction of 0.6·L<x<1.5·L.
 3. The center-feed roll unit according to claim 1, wherein the diameter of the untwisting insert element is larger than 0.1·D_(min) and smaller than 0.99·D_(min).
 4. The center-feed roll unit according to claim 1, wherein the untwisting insert element is made of glass, wood, silicone, rubber, metal or plastic material.
 5. The center-feed roll unit according to claim 1, wherein the untwisting insert element is made of disposable material.
 6. The center-feed roll unit according to claim 1, wherein the untwisting insert element has a smooth surface.
 7. The center-feed roll unit according to claim 1, wherein the untwisting insert element has a cross-sectional shape which is one of circular, semi-circular, elliptical, crescent shaped, prismatic, and triangular.
 8. The center-feed roll unit according to claim 1, wherein the untwisting insert element comprises separate parallel rods.
 9. The center-feed roll unit according to claim 1, wherein the untwisting insert element is a flat elongate strip.
 10. A dispenser for a web of material, including a center-feed roll unit according to claim
 1. 11. The dispenser according to claim 10, wherein the untwisting insert element is removably attached to the dispenser close to the first end of the center-feed roll loaded into the dispenser.
 12. The dispenser according to claim 11, wherein the untwisting insert element is attached to the dispenser via one of a form-fit connection, a snap fit, a slide-in connection, and an adhesive.
 13. The dispenser according to claim 11, wherein the untwisting insert element is hingedly attached to the dispenser.
 14. The dispenser according to claim 10, wherein the untwisting insert element is provided as a separate part insertable into the center-feed roll before the center-feed roll is loaded into the dispenser.
 15. The center-feed roll unit according to claim 1, the center-feed roll having a maximum inner diameter D_(max) at full consumption of the web of material, wherein the longitudinal extension x of the untwisting insert element equals at least half of the maximum inner diameter D_(max) of the center-feed roll.
 16. The center-feed roll unit according to claim 1, the untwisting insert element having an extension x in the longitudinal direction of 0.8·L<x<L.
 17. The center-feed roll unit according to claim 1, wherein the diameter of the untwisting insert element is larger than 0.6·D_(min) and smaller than 0.95·D_(min).
 18. The center-feed roll unit according to claim 1, wherein the diameter of the untwisting insert element is larger than 0.8·D_(min) and smaller than 0.9·D_(min).
 19. The center-feed roll unit according to claim 1, wherein the untwisting insert element is made of cardboard. 